A lot of folks are big believers in trying to be as
"organic" as possible when controlling ailments in their plant
collections, or just trying to spruce them up. We strongly recommend
AGAINST preventive use of insecticides and fungicides, as there is a fairly
strong tendency to breed resistant strains. Instead, we suggest that you
take the time to carefully inspect your collection, and treat problems as soon
as they arise.
Below are a number of concoctions that come highly recommended,
but please remember that you're using them at your own risk, and that of your
plants, and the I can take no responsibility for the outcome.
Your choice of home-made insecticide should be based upon what
you're trying to eliminate.
Soft-bodied bugs, such as aphids
& mealie bugs:
Straight 70% or 90% isopropyl rubbing alcohol - touch insects
with a soaked cotton swab, or for larger infestations, spray the entire affected
plant, being sure to thoroughly wet all surfaces. Repeat every 3 days for
about 2 weeks. (I have never experienced any problems with buds, flowers,
or any part of the plant when using an alcohol spray.)
Garlic/pepper spray - liquefy 2 bulbs of garlic and 2 hot peppers in a blender 1/2 to 2/3 full of water. Strain
to remove the solids and add enough water to the garlic/pepper juice to make 1 gallon of concentrate. Use 1/4 cup of concentrate per gallon of spray. To make garlic tea, simply omit the pepper and add another bulb of garlic. Add two tablespoons of blackstrap molasses for more control.
Insects that have hard shells, such as
scale, and thrips:
Mix 1 teaspoon (5 ml) each cooking oil and liquid dishwashing
soap or detergent in a quart (liter) of water. Concentrations are not
critical - some recommend a tablespoon (15 ml) of oil be used. Shake well,
and spray the plant, being sure to thoroughly wet all surfaces. Repeat
every 3 days for about 2 weeks. (The soap breaks down the waterproof, waxy
coating on the insects' shells, and the oil will smother them.)
A WORD OF CAUTION ABOUT OILS: CLICK
General-purpose insect spray:
One cup (250 ml) each Formula 409 or Fantastik household
cleaner/degreaser and isopropyl rubbing alcohol and 2 cups water, making a quart
or liter of spray. Use the same as the formulas above. (I've not
tried this one.)
Mix three tablespoons of Dr. Bronner's Peppermint Pure-Castile Soap and 3/4 cup isopropyl rubbing alcohol in a quart bottle, tehn add water to fill it up. Supposed to be a good, general purpose insecticide.
Orange Plus, a household cleaner made from byproducts of
orange juice production, can be sprayed directly on plants to eliminate
insects. (I suspect other concoctions made using citrus oils may also
be effective, but have no knowledge or experience concerning them.)
in a 1 quart spray bottle mix 1 tsp Murphy's Oil Soap, 1 tsp
Sunspray (or cooking oil), 1tbs lemon juice, and fill the rest with 1/2
water and 1/2 alcohol.
Melt about 1/4 pound of candle wax, then slowly stir in about
1/4 cup sugar and 4 ounces boric acid powder (available at your local drug
store). When thoroughly mixed, pour into a pan, creating a 1/4" to
1/2" thick slab. Cut or break into chunks, and distribute around the
greenhouse. If you decide to try this indoors, be sure to keep them away
from children and animals.
A surprising - and no doubt smelly - ant repellant is
fermented cow manure tea. Put about a gallon volume of fresh manure in
a 5-gallon bucket and top it up with water. Cover and let stand for a
couple of weeks or more until it's fully "cured." Spray
around the greenhouse and under the benches. (CJ Maciejeski claims
this keeps fire ants away down in Houston, and if it works for them...)
Here's another volunteered from the
world of cyberspace: raw grits or corn meal! Sprinkle
them in an area where ants are attracted, and they will
gobble them up. Later they will swell in their
bellies. (Need I say more?)
Another contributor verified that the grits or corn meal works, but only for
larger ants. For the small ones, try sprinkling some bath powder
Along those same lines, a 50/50 mix of powdered
(confectioner's) sugar and baking soda is supposed to be effective against
OK, another one volunteered by a reader - aspartame!
You know...Nutrasweet, the sugar substitute? Apparently it is
attractive to them, is taken back to the colony, and kills the lot.
This one is even supposed to be effective against fire ants. You may
find it necessary to dampen the powder or granules to make it attractive to
Place small, open containers of eucalyptus oil in the
growing area. The vapors will discourage critters from
approaching. (Yeah, it's going to smell like a Hall's Cough Drop
factory, but it's good for opening your sinuses, too - a la Vick's
Vapo-Rub.) Eucalyptus oil has also been shown to be an effective
fungicide, but I know that a dispersion in water and alcohol, when sprayed
directly on the plant, will damage flower buds, so I can't recommend that
Those of you who frequent the rec.gardens.orchids newsgroup know
of my "crusade" for the use of cinnamon as a fungicide. I've
done a lot of digging, and it turns out that the chemicals in the bark have all
sorts of medicinal applications (I've even cured athlete's foot with my alcohol
Choose the consistency that is best for your situation:
Apply normal, household cinnamon powder directly to the affected
part of the plant by dusting heavily. This has proven to be a good way to
control slime mold and mushrooms in the mulch in my outdoor flower beds,
Mix cinnamon powder with sufficient casein-based glue (Elmer's)
to make a thick, brown paste. Apply to the wound and let dry. The
Elmer's Glue is water soluble, but resists washing-off quite well. This is
the preference for mounted plants that get watered or misted frequently.
An alternative to the Elmer's Glue, but just as waterproof
and long-lasting is made by mixing cinnamon powder and cooking oil to form a
thick paste. (Thanks to John Kawamoto!)
You can prepare a cinnamon spray using either alcohol or water
as your solvent. The alcohol infusion is faster to prepare, and offers
some insecticidal properties as well. This is my preferred method, and has
been effective at eliminating all sorts of fungus problems, including damping-off
of deflasked seedlings.
Put 2 tablespoons (30 ml) of cinnamon powder in a pint (500 ml)
of isopropyl rubbing alcohol. Shake well and let stand overnight.
Filter the solution to remove the sediment (coffee filters work well), and use
the brown liquid as a spray. (While it's not a big problem for most orchid
growers, I've heard that this is good for powdery mildew, as well.)
Put the cinnamon powder in hot water. Shake well and let
stand for several days. Filter and use as above. (Some feel that the
alcohol can be too desiccating when used on seedlings.)
Here's another alternative - Ground Corn Meal
Place one cup of whole ground corn meal in an old sock or
panty hose leg and immerse in a gallon of water. Let stand for a
couple of days, then use the liquid as a spray.
If your phals look like they're starting to get crown rot,
sometimes simply pouring some straight-from-the-drug store hydrogen peroxide
on the wound can stop the process. Just be sure to tilt the plant and
drain the grown after about five minutes so it can dry.
General Purpose Spray:
Put one cup of the alcohol cinnamon-extract in a pint bottle, add two
tablespoons of liquid dishwashing detergent, and top up with water. Use as
a spray. The soap and alcohol are good insecticides, while the cinnamon is
Mix approximately 1/3 cup milk into a quart of water, and
spray. I have not tested this one, but even if it doesn't work, you
end up with shiny leaves!
Mix 3 tablespoons cooking oil, 1 tablespoon liquid
dishwashing detergent, and 1 tablespoon baking soda in a gallon of water;
spray at three-day intervals for powdery mildew.
SLUG & SNAIL
Trap: Put a plate or plant saucer full of fresh beer on the floor;
snails and slugs will be attracted to it, fall in and drown. (Stale beer,
has apparently been shown in university studies, to be a repellant, not
Spray: Mix one cup household (non-sudsy) ammonia with
water, and spray directly on the critters.
Spray: Don't throw away the left-over coffee!
Mix it 50/50 with water (some say use it straight), and spray. I add
about 2 ounces per gallon rubbing alcohol to keep mold from growing on the
liquid surface when the stuff is stored. Seems
to work great on Bush Snails.
If you suffer from slugs climbing up onto the benches and
attacking your plants, there are several ways of blocking their path, ranging
from mechanical to chemical:
Mechanical: Spread a layer of Diatomaceous Earth on the
benches, around your plants. The material - the skeletons of microscopic
sea creatures (diatoms) - is almost pure silicon dioxide, and has very sharp
points and edges that discourage the passage of the creatures. The
material sold as a microfiltration medium for aquariums probably won't do much.
If you can find horticultural grade material, it is coarser and has much
sharper edges that make a great barrier.
Mechanical II: Staple wet/dry sandpaper to the legs of
your benches, grit side out.
Mechanical / Electrochemical: Tightly wrap the legs of your bench with a
2" (5cm) wide strip of copper foil, being sure to apply it tightly enough
to avoid gaps. The copper is supposed to create some sort of uncomfortable
electrochemical effect when in contact with the "slime" secreted by
the critters. I suppose it's like biting on a piece of foil if you have
metal fillings in your teeth!
Chemical: Apply a thick layer of the product Tree
Tanglefoot around the legs of the bench. Available a most good garden
centers, it is sold as a bird repellent for ornamental trees, it contains a
castor-bean extract that repels slugs and snails.
If you just want to lure the critters away from your plants
so you can dispose of them, try putting slices of raw potato near the potted
plants on the bench. The slugs and snails can be found on the
underside in the morning. (Thanks to Janet Price.)
Boil approximately 2 cups of water, 2 teaspoons or a packet
of yeast, and 2 tablespoons of honey together. The relative
proportions aren’t important. Mix, and then put
it out in shallow trays or pans for the snails. Refresh every week or two. (Thanks to Tania Nowell)
ALGAECIDE (for cooling pads):
Place one cup of whole ground corn meal in an old sock or
panty hose leg and tie a knot in it to contain the meal. Place in the
water tank for the cooling system. The algae will dissolve in a few
days. Note: I have no idea if this methodology can be used for
algae growing in pots.)
Spray full-strength household vinegar on weeds, repeat daily
as needed. This is NOT to be used for weeds growing in the pots of your other
plants, but is good in driveways, walkways, the greenhouse floor, patios, etc.
Add one ounce of household chlorine
bleach to a gallon of water and spray on utensils,
benches, even your plants to control a wide variety of
pathogens. It even helps control algae.
If you live in an area where the water has a fair amount of
dissolved minerals, or if you mist with a fertilizer solution, the leaves of
your plants can become dull in appearance. Folks may warn you that these
treatments can clog the pores (stomata) on the leaves, but I've never seen a
Pineapple juice, or any citrus juice (lemon, lime, orange),
when rubbed onto the leaves with a soft cloth or paper towel will also
remove such deposits so your leaves will be nice and shiny. I suppose
the acidity reacts with the mostly alkaline deposits. (Thanks to CJ Maciejeski)
Reka reports that stale beer may also be used for shining up
leaves, although we're both at a loss for how to get stale beer, as it never
gets that way around our houses!
Mix about a 50% dispersion of whole milk in a quart of
water. Using a soft cloth or paper towel, wipe the leaf surfaces with the
Similar to the milk above, dilute mayonnaise with water to form
a thin paste. Again, apply using a soft cloth or paper towel, being sure
that you wipe off as much of the paste as you can.
If you like "going natural," but don't want to bother making
up your own stuff, I have formulated a great spray - Rise & Shine™ - that is
a great leaf cleaner and shine. Go to "The Store" to see more.
"DO EVERYTHING" SPRAY:
Fermented Compost Tea - take about one- to two cups of some really
well-composted organic matter (the stuff at the bottom of the pile), place it in
a cloth bag (an old sock will work), and immerse it in a gallon of water at room
temperature. Let it stand overnight or longer until you have a dark
liquid. Remove the "tea bag" and let the container sit outdoors for about
Remove the scum that forms at the surface, filter the
liquid and spray.
Supposedly, this brew will be loaded with
bacteria and other microorganisms that attack pretty much all of the fungi and
diseases that harm plants. (It has also been suggested that the
unfermented brew from above, once diluted to about 20% in water, is as close to
the food source an orchid sees in nature as you can get!)
CROWN ROT TREATMENT:
rot is caused by letting water sit in the folds between leaves, resulting in a
bacterial or fungal infection, or even both. Prevention is the key, so
water or mist early in the day so the stuff has time to dry by nightfall.
If you do get a case of crown rot:
Pour a liberal amount of hydrogen peroxide in the wound
and let it stand for about 5 minutes to kill the infecting agents.
Tilt the plant to pour the liquid out of the crown.
Let the plant dry completely.
Sprinkle with dry cinnamon.
Treat the plant normally, being sure to keep the wound